Method for polishing a semiconductor substrate member

ABSTRACT

A polishing slurry prepared by dispersing in a dispersion medium, abrasive grains comprised of a material having a solubility in the dispersion medium at 25° C., of 0.001 g/100 g or higher is used to effectively remove any abrasive grains standing adherent to the surfaces of objects to be polished or the interiors of polishing apparatus after polishing.

This application is a Divisional application of application Ser. No.09/797,940, filed Mar. 5, 2001.

This application is based on Japanese Patent Application No. 2000-164650filed in Japan, the contents of which are incorporated hereinto byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a polishing slurry suited for the polishing ofelectronic materials, magnetic materials and optical materials, apolishing method using the polishing slurry, and a process forfablicating semiconductor devices.

2. Description of the Related Art

In recent years, in order to achieve higher integration of semiconductorintegrated circuits, wiring techniques more and more trend toward finerand more multilayered wiring. This has brought about a tendency toward alarger difference in height of interlayer insulating films. Because ofthis difference in height of interlayer insulating films, any wiringformed thereon may have a low processing precision and a lowreliability. Hence, polishing techniques for improving smoothness ofinterlayer insulating films have become very important. For example,Japanese Patent Application Laid-open No. 9-22885 discloses chemicalmechanical polishing of interlayer insulating films formed onsemiconductor wafers.

Polishing slurries conventionally used for semiconductor substrate mayinclude, e.g., as disclosed in Japanese Patent Application Laid-open No.11-111657, an acidic (about pH 3) alumina slurry, a neutral silicaslurry having silica particles dispersed therein as abrasive grains, andan alkaline silica slurry prepared by adding sodium hydroxide or thelike to this neutral slurry. Besides these, as abrasive grains, thispublication further discloses oxide particles such as alumina particles,titanium oxide particles and zirconium oxide particles obtained byhydrolyzing metal alkoxides.

Abrasive grains comprised of metals (inclusive of semi-metals) or metaloxides, used in these conventional polishing slurries, adhere to thesurfaces of objects to be polished and to the interiors of polishingapparatus, e.g., to pads, dressers and so forth, and remain thereonafter polishing to damage smoothness and film properties unless nomeasure is taken therefor. Accordingly, as a post treatment ofpolishing, as disclosed in, e.g., Japanese Patent Application Laid-openNo. 9-22885, washing with an alkaline solution or scrubbing washing hasbeen carried out. However, for the abrasive grains comprised of metals(inclusive of semi-metals) or metal oxides, used in these conventionalpolishing slurries, it has been difficult to be completely removed bywashing, and has been very difficult to be removed by washing especiallywhen the abrasive grains stand stuck in the semiconductor substrate.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide apolishing slurry whose abrasive grains having remained after polishingare removable with ease, a polishing method and a semiconductor devicefabrication process which make use of this polishing slurry.

To achieve the above object, the present invention provides a polishingslurry comprising a dispersion medium and abrasive grains dispersed inthe dispersion medium; the abrasive grains comprising a material havinga solubility in the dispersion medium at normal temperature (25° C.), of0.001 g/100 g or higher. The present invention also provides a polishingslurry comprising a dispersion medium and abrasive grains dispersed inthe dispersion medium; the abrasive grains comprising organic matter. Ineither of inorganic matter and organic matter, the abrasive grains maypreferably have a solubility in the dispersion medium, of 0.001 g/100 gor higher, and more preferably 0.1 g/100 g or higher. In the case whenthe abrasive grains are comprised of organic matter, it may preferablyhave a melting point of 30° C. or above so that it can be present in thestate of a solid in usual polishing steps.

The present invention still also provides a polishing method ofpolishing an object to be poslished by using any of these polishingslurries of the present invention, and a process for fabricating asemiconductor device by using such a method.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, objects and advantages of the presentinvention will become more apparent from the following description whentaken in conjunction with the accompanying drawings wherein;

FIG. 1A and FIG. 1B illustrate basic concept of the present invention;and

FIG. 2A to FIG. 2D are a cross-sectional views showing some steps in aprocess of producing a semiconductor substrate.

DETAILED DESCRIPTION OF THE DRAWINGS

On the abrasive grains contained in the polishing slurry of the presentinvention, there are no particular limitations as long as they are thosehaving a solubility in its dispersion medium, of 0.001 g/100 g or higherat normal temperature, and capable of being present in the dispersionmedium in the state of a solid. They may be comprised of inorganicmatter or organic matter, but may preferably be those which do notaffect any properties of objects to be polished. For example, when theobjects to be polished are semiconductor substrate members, it ispreferable to use materials which do not contain sodium, calcium or thelike.

Inorganic compounds usable as the abrasive grains in the presentinvention may include;

Ag compounds such as AgBr, AgCl, AgClO₄, Ag₂CrO₄, AgF, AgNO₃, Ag₂O andAg₂ SO₄;

Al compounds such as AlCl₃, Al(NO₃)₃, Al₂ (SO₄)₃, Al(ClO₄)₃.9H₂ O,AlCs(SO₄)₂.12H₂O, AlF₃.3H₂O, AlK(SO₄)₂.12H₂O, AlNH₄(SO₄)₂.12H₂O andAlNa(SO₄)₂.12H₂O;

As compounds such as As₂O₃;

Ba compounds such as BaBr₂, BaCl₂, Ba(ClO₃)₂, BaI₂, Ba(NO₂)₂, Ba(NO₃)₂,Ba(OH)₂, BaS and BaSO₄;

Be compounds such as Be(ClO₄)₂, Be(NO₃)₂ and BeSO₄;

Br compounds such as CaBr₂;

Ca compounds such as CaCO₃, CaCl₂, Ca(ClO₄)₂, CaCrO₄, CaI₂, Ca(IO₃)₂,Ca(NO₃)₂, Ca(OH)₂ and CaSO₄;

Cd compounds such as CdBr₂, CdCl₂, Cd(ClO₃)₂, Cd(ClO₄)₂, CdI₂, Cd(NO₃)₂and CdSO₄;

Ce compounds such as Ce₂ (SO₄)₃, Ce(IO₃)₃, Ce₂Mg₃ (NO₃)₁ ₂.24H₂O, Ce(NH₄)₂ (NO₃)₅ .4H₂O, Ce(NO₃)₄; Ce(NH₄)(NO₃)₆ and Ce₂ (WO₄)₃;

Co compounds such as CoBr₂, CoCl₂, Co(ClO₃)₂, CoI₂, Co(NO₃)2 and CoSO₄;

Cr compounds such as Cr(NO₃)₃ and CrO₃;

Cs compounds such as CsCl, CsClO₃, CsClO₄, CsI, CsNO₃ and Cs₂SO₄;

Cu compounds such as CuBr₂, CuCl₂, Cu(ClO₃)₂, Cu(NO₃)₂, CuSO₄, CuCl₂,Cu(ClO₄)₂.6H₂O, CuCrO₄, CuF₂.2H₂O, CuI, CuI₂, CuK₂ (SO₄).6H₂O,Cu(NH₄)₂Cl₄.2H₂O, Cu(NH₄)₂(SO₄)₂.6H₂O, CuSeO₄.5H₂O, Cu(SiF₆).4H₂O andCu(SO₃ NH₂)₂;

Fe compounds such as FeBr₂, FeCl₂, FeCl₃, Fe(ClO₄)₂, Fe(ClO₄)₃,Fe(NO₃)₂, Fe(NO₃)₃, FeSO₄, FeF₃.3H₂O, FeK₂(SO₄)₂.6H₂O, FeNH₄(SO₄)₂.12H₂Oand Fe(NH₄)₂(SO₄)₂.6H₂ O;

Ge compounds such as GeO₂;

B compounds such as H₃BO₃;

Cl compounds such as HClO₄.H₂ O;

P compounds such as H₃PO₄;

Hg compounds such as HgBr₂, HgCl₂, Hg₂Cl₂, and Hg(ClO₄)₂;

I compounds such as I₂;

In compounds such as InCl₃;

K compounds such as KBr, KBrO₃, K₂CO₃, KCl, KClO₃, KClO₄, K₂CrO₄,K₂Cr₂O₇, KF, K₃[Fe(CN)₆], K₄[Fe(CN)₆], KHCO₃, KH₂PO₄, K₂HPO₄, KI, KIO₃,KIO₄, KMnO₄, K₂MnO₄, KNO₃, KOH, K₃PO₄, KSCN, K₂SO₃, K₂SO₄, KHF₂, KHSO₄and KNO₂;

La compounds such as LaCl₃, La(NO₃)₃ and La₂(SO₄)₃;

Li compounds such as LiBr, LiBrO₃, Li₂CO₃, LiCl, LiClO₄, Li₂CrO₄, LiI,LiNO₃, LiOH and Li₂SO₄;

Mg compounds such as MgBr₂, MgCO₃, MgCl₂, Mg(ClO₃)₂, Mg(ClO₄)₂, MgCrO₄,MgMoO₄, Mg(NO₃)₂, MgSO₃ and MgSO₄;

Mn compounds such as MnBr₂, MnCl₂, Mn(NO₃)₂ and MnSO₄;

Mo compounds such as MoO₃;

NH₄ compounds such as NH₄Br, NH₄Cl, NH₄ClO₄,(NH₄)₂, CrO₄, (NH₄)Cr₂O₇,NH₄F, NH₄HCO₃, NH₄H₂PO₄, (NH₄)₂HPO₄, NH₄I, NH₄NO₃, NH₄SCN, (NH₄)₂SO₄,(NH₄)₂S₂O₈, (NH₃ OH)Cl, (NH₄)₂CO₃, NH₄HF₂, NH₄N₃ and NH₄NO₃;

Na compounds such as NaBO₂, NaBr, NaBrO₃, NaCN, Na₂CO₃, NaCl, NaClO₂,NaClO₃, NaClO₄, Na₂CrO₄, Na₂Cr₂O₇, NaF, Na₄[Fe(CN)₆], NaHCO₃, NaH₂PO₄,Na₂HPO₄, NaI, NaIO₃, NaMnO₄, NaNO₂, NaNO₃, NaOH, Na₄P₂O₇, Na₂S, NaSCN,Na₂SO₃, Na₂SO₄, Na₂S₂O₃, Na₃VO₄ and Na₂WO₄;

Nd compounds such as NdCl₃, Nd(NO₃)₃ and Nd₂(SO₄)₃;

Ni compounds such as NiBr₂, NiCl₂, Ni(ClO₃)₃, Ni(ClO₄)₂, Ni(NO₃)₂ andNiSO₄;

Pb compounds such as PbBr₂, PbCl₂, PbI₂, Pb(NO₃)₂ and PbSO₄;

Pr compounds such as PrCl₃, Pr(No₃)₃ and Pr₂(SO₄)₃;

Pt compounds such as PtCl₄, [PtCl(NH₃)₅]Cl₃ and [Pt(NH₃)₆]Cl₄;

Rb compounds such as RbBr, RbCl, RbClO₃, RbClO₄, Rb₂CrO₄, Rb₂Cr₂O₇, RbI,RbNO₃ and Rb₂SO₄;

Sb compounds such as SbCl₃;

Se compounds such as SeO₂;

Sm compounds such as SmCl₃;

Sr compounds such as SrBr₂, SrCl₂, Sr(ClO₃)₂, Sr(ClO₄)₂, SrI₂, Sr(NO₂)₂,Sr(NO₃)₂, Sr(OH)₂ and SrSO₄;

Th compounds such as Th(NO₃)₄ and Th(SO₄)₂;

Tl compounds such as TlBr, TlCl, TlClO₄, TlNO₂, TlNO₃, TlOH and TlSO₄;

U compounds such as U(SO₄)₂, UO₂CrO₄, UO₂(NO₃)₂ and UO₂SO₄;

Y compounds such as YBr₃, YCl₃, Y(NO₃)₃ and Y₂(SO₄)₃;

Yb compounds such as Yb₂(SO₄)₃; and

Zn compounds such as ZnBr₂,ZnCl₂, Zn(ClO₂)₂, Zn(ClO₃)₂, Zn(ClO₄)₂, ZnI₂,Zn(NO₃)₂ and ZnSO₄.

Of these, it is preferable to use Al compounds, Ce compounds, Cucompounds, Fe compounds and/or NH₄ compounds. In particular, NH₄compounds are preferred because they do not deteriorate anysemiconductor products. As the most preferred materials for abrasivegrains, they may include NH₄Cl, NH₄ClO₄, NH₄HCO₃, Ce₂(SO₄), CuCl₂ andCuSO₄.

As specific examples of the organic matter usable as the abrasive grainsin the present invention, it may include organic acids (organic acidsand esters or salts thereof), alcohol compounds, ether compounds,phenolic compounds and nitrogen-containing compounds. These organiccompounds are commonly formed of crystals softer than inorganic matterand hence may hardly scratch polishing objects. Thus, these areparticularly advantageous for polishing soft objects such as insulatingfilms formed of organic materials or oxides of metals or semi-metals.

The organic acids may include adipic acid, acetylsalicylic acid, saltsof benzoic acid (such as potassium benzoate and strychinine benzoate),o-nitrobenzoic acid, p-hydroxybenzoic acid, carbamic esters (such asethyl carbamate), salts of formic acid (such as potassium formate andmagnesium formate dihydrate), citric acid, citric acid hydrate,chloroacetic acid (i.e., α-chloroacetic acid, β-chloroacetic acid orγ-chloroacetic acid), succinic acid, salts of oxalic acid (such asammonium oxalate and potassium oxalate), oxalic acid hydrate, tartaricacid (i.e., (+)-tartaric acid or (−)-tartaric acid), nicotinic acid,nicotinic acid hydrochloride, maleic acid, malonic acid, DL-mandelicacid, DL-malic acid, salts of valeric acid (such as silver valerate),salts of gluconic acid (such as potassium gluconate), salts of cinnamicacid (such as calcium cis-cinnamate), salts of acetic acid (such asuranyl acetate dehydrate, calcium acetate, cesium acetate, magnesiumacetate tetrahydrate and lithium acetate dehydrate), salts of salicylicacid (such as ammonium salicylate, potassium salicylate hydrate),trichloroacetic acid, salts of naphthalene sulfonic acid (such asammonium 1-naphthalene sulfonate and ammonium 2-naphthalene sulfonate),hippuric acid, hippuric esters (such as ethyl hippurate), salts ofphenoxyacetic acid (such as ammonium phenoxyacetate), salts of fumaricacid (such as calcium fumarate trihydrate), salts of butyric acid (suchas calcium butyrate hydrate and barium butyrate), and amino acids.

As the amino acids, usable are, e.g., L-ascorbic acid, glycine,DL-α-aminoisobutyric acid, aminobutyric acid (such as DL-α-aminobutyricacid, 3-aminobutyric acid or 4-aminobutyric acid), aminopropionic acid(such as DL-alanine, L-alanine or β-alanine), orotic acid ester salts(such as ethylammonium orotate and benzylammonium orotate), andDL-valine.

The alcohol compounds may include saccharides such as D-glucose,D-glucose hydrate, sucrose and D-mannitol, and salt of glycerophosphoricacid (such as calcium glycerophosphate). The ether compounds may include18-crown-6. Incidentally, the saccharides listed here aremonosaccharides and disaccharides, and may also be trisaccharide orhigher polysaccharides.

The phenolic compounds may include catechol, 2-naphthol, m-nitrophenol,hydroquinone, resorcinol, glycidylglycine and pyrogallol.

The nitrogen-containing compounds may include amine compounds, amidecompounds, imide compounds, nitro compounds, ammonium salts, andheterocyclic compounds containing nitrogen as a heteroatom. Statedspecifically, usable are acetanilide, acetamide, aniline hydrochloride,ethylenediaminetetraacetic acid, caffeine, urea, thiourea,2,4,6-trinitrotoluene, phenylenediamine (i.e., o-phenylenediamine,α-m-phenylenediamine, β-m-phenylenediamine or p-phenylenediamine),acrylamide, antipyrine, quinine salts (such as quinine hydrochloridedihydrate and quinine sulfate heptahydrate), cocaine hydrochloride,codeine phosphate dehydrate, succinimide hydrate, taurine, tetraethylammonium salts (such as tetraethylammonium chloride, tetraethylammoniumbromide and tetraethylammonium iodide), tetrapropylammonium salts (suchas tetrapropylammonium iodide), tetramethylammonium salts (such astetramethylammonium bromide and tetramethylammonium iodide),tris(hydroxymethyl)aminomethane, pyrazole, pteridine andhexamethylenetetramine.

Of these, adipic acid, citric acid hydrate and malonic acid arepreferred because the metal copper can be prevented from corroding.Sucrose is also preferred because it makes it easy to dispose of wasteliquor and does not deteriorate any semiconductor products.

There are no particular limitations on the dispersion medium as long asit is a liquid capable of dissolving these abrasive-grain materials. Forexample, the following materials (1) to (5) are usable as the dispersionmedium.

(1) An acidic solution (preferably pH 2 to 4) containing at least oneacid selected from hydrofluoric acid, hydrochloric acid, sulfuric acid,nitric acid, acetic acid and organic acids.

(2) An alkaline solution (preferably pH 9 to 11) containing at least onebase selected from ammonium hydroxide, potassium hydroxide, sodiumhydroxide and amines.

(3) A solution containing a salt of the above acid with the above base.

(4) Water.

(5) An organic solvent (preferably an aliphatic alcohol having 1 to 5carbon atoms.

The dispersion medium may optionally further contain hydrogen peroxideand ammonium fluoride, and may also appropriately contain additives suchas an anti-corrosive and a dispersant. For the purpose of stabledispersion of the abrasive grains, it is desirable for theabrasive-grain material to stand dissolved in saturation in thedispersion medium. The abrasive-grain material standing dissolved in thedispersion medium may also function as a surface-active agent, adispersant, an anti-corrosive, a buffer or the like.

In the present invention, the dispersion medium may optionally stillfurther contain at least one of a cationic surface-active agent, ananionic surface-active agent, an amphoteric surface-active agent and anorganic solvent. Such various surface-active agents may each be used ina concentration not higher than the critical micellar concentration ornot higher than 0.01 mol/L based on the total weight of the dispersant,in order to avoid agglomeration of abrasive grains and ensure a stabledispersibility.

The abrasive grains in the present invention may have any grain diameterwithout any particular limitations, and may appropriately be determinedin accordance with polishing objects, smoothness required, and so forth.To obtain abrasive grains having a specific size, a method is availablein which the above abrasive grains, having been dried, are pulverizedand then classified with a sieve. Another method is also available inwhich a solution having the abrasive grains dissolved therein isatomized by means of an atomizer, and the abrasive grains standingatomized are collected and then dried, followed by classification with asieve.

The abrasive grains in the present invention may be dispersed in thepolishing slurry in a quantity (i.e., quantity of abrasive grainspresent in the form of a solid, per unit volume, or weight, of thepolishing slurry) which may appropriately be determined in accordancewith polishing objects, smoothness required, polishing rate and soforth, and may preferably be in an amount of from 1 to 50% by weight,and more preferably from 1 to 20% by weight, based on the total weightof the polishing slurry. In order to leave the abrasive grains in theform of a solid without being dissolved in the dispersion medium, thepolishing slurry may be prepared by adding the abrasive grains to thedispersion medium in a quantity exceeding the solubility of theabrasive-grain material. Accordingly, the quantity of the abrasivegrains used may appropriately be determined in accordance with polishingconditions (the quantity and type of the slurry, pH, temperature,additives and so forth).

The polishing slurry of the present invention makes use of the abrasivegrains that can be dissolved in the dispersion medium. Hence, thequantity in which the abrasive grains are dispersed in the polishingslurry can dynamically be changed in the course of polishing, bychanging, e.g., the quantity and/or temperature of the dispersionmedium. Stated specifically, in the present invention, the quantity ofdispersion of the abrasive grains to be dispersed in the polishingslurry in the form of a solid can be changed by changing the quantity ofthe dispersion medium in the polishing slurry. More specifically, in thepresent invention, the dispersion medium may be added to the polishingslurry so as to make the abrasive grains dissolve in part in thedispersion medium to lower their quantity of dispersion. Conversely, thedispersion medium may be removed in part from the polishing slurry so asto recrystallize the abrasive-grain material having stood dissolved inthe dispersion medium, thus abrasive grains can be made to form anew tomake the abrasive grains become dispersed in a larger quantity. Also,the temperature of the polishing slurry may be changed so as to changethe solubility of abrasive grains in the dispersion medium to change thequantity of dispersion of the abrasive grains dispersed in the polishingslurry in the form of a solid.

The present invention also provides a polishing method of polishing anobject to be polished, by using the polishing slurry of the presentinvention, and a process for fabricating a semiconductor device by usingthis polishing method. The polishing slurry of the present invention issuited for polishing electric or electronic materials, magneticmaterials and optical materials, such as resins, conductors andceramics, and is especially suited for polishing conductor films andinsulating films, in particular, those of semiconductor devices, wiringsubstrates and so forth, in the manufacture of electric or electronicapparatus for which a high smoothness and a high cleanness are required.

For example, as shown in FIG. 1A, abrasive grains 1 stand adherent tothe surface of a semiconductor wafer member 2, after interlayerinsulating films such as plasma silicon oxide films, CVD (chemical vapordeposition) silicon oxide films and PVD (physical vapor deposition)silicon oxide films have been smoothed by chemical mechanical polishing.However, according to the present invention, the abrasive-grain materialincreases in solubility because of the heat generated by polishing, andhence the abrasive grains become dissolved in the dispersion medium, sothat the abrasive grains 1 may less adhere to the surface of the objectto be polished. Also, the abrasive grains 1 having adhered may bedissolved in a wash liquid, whereby, as shown in FIG. 1B, they cancompletely be removed with ease. Thus, compared with conventionalpolishing slurries, a clean polished surface can much more easily beobtained. Incidentally, as the wash liquid, any liquid capable ofdissolving the abrasive-grain material, such as the solvent used in thedispersion medium, may appropriately be selected.

According to the present invention, any abrasive grains standingadherent to the surfaces of objects to be polished such as semiconductorsubstrates or to the interiors of polishing apparatus after polishingcan be removed in a good efficiency, and hence semiconductor productsand so forth can be manufactured at a low cost, in a high quality and ata high yield. Moreover, according to the present invention, the quantityof dispersion of abrasive grains in the dispersion medium can becontrolled with ease, and hence the polishing wear or polishing rate candelicately be controlled. Also, since the abrasive grains can be made todissolve, the disposal of waste liquid can be made without separatingthe abrasive grains from the polishing slurry. Incidentally, the presentinvention is applicable not only to semiconductor wafers but also tosubstrates of thin-film devices, thin-film disks and the like.

THE PREFERRED EMBODIMENT

Examples of the present invention are given below, which are describedwith reference to FIG. 2A to FIG. 2D. The present invention is by nomeans limited to these Examples.

In the present Examples, polishing slurries were prepared in whichabrasive grains (grain diameter: 150 nm) comprised of compounds as shownin Table 1 were dispersed in an amount of 30 g per 100 g of polishingslurry, and, using these, oxide films were polished to smoothsemiconductor substrate surfaces. In Table 1, the solubility of eachcompound at normal temperature (25° C.) is shown together.

TABLE 1 Abrasive-grain Solubility material (%) Example 1 NH₄Cl 28.2Inorganic Example 2 NH₄ClO₄ 21.0 matter Example 3 NH₄HCO₃ 19.9 Example 4Ce₂(SO₄)₃ 7.59 Example 5 CuCl₂ 42.8 Example 6 CuSO₄ 18.2 Example 7adipic acid 2.4 Organic citric acid matter Example 8 monohydrate 62.0Example 9 succinic acid 7.5 Example 10 ammonium oxalate 5.0 Example 11sucrose 67.0 Example 12 malonic acid 32.2

(1) Preparation of Polishing Slurry:

First, to a solution prepared by dissolving NH₄HCO₃ particlessaturatedly in an ammonia solution with a pH adjusted to 11, abrasivegrains having a primary particle diameter (particle diameter ofindividual abrasive grains) of 30 nm and a secondary particle diameter(particle diameter of abrasive grains standing agglomerated) of 150 nmwere further added in an amount of 30 g per 100 g of polishing slurry,and dispersed therein to obtain each polishing slurry.

(2) Polishing Conditions:

As the polishing apparatus, a polishing apparatus manufactured byApplied Materials, Inc. was used, and polishing objects were polishedsetting the number of revolutions of the head at 90 rpm and the numberof revolutions of the platen at 90 rpm and feeding a 25° C. polishingslurry at a feed rate of 200 mL/minute. Here, polishing temperature wascontrolled to 25° C. so that the liquid temperature did not rise duringpolishing.

(3) Production of Semiconductor Substrate Member:

First, as shown in FIG. 2, an oxide film 4 was formed on a semiconductorsubstrate 3, and an Al wiring 5 was further formed thereon to produce asemiconductor substrate member having a difference in height at thesurface [FIG. 2, (a)]. On the surface of this substrate member, asilicon nitride film 6 serving as a polishing stopper layer was soformed as to cover the uncovered surfaces of the oxide film 4 and wiring5 [FIG. 2, (b)].

Subsequently, an oxide film 7 was so formed by CVD as to fill up thedifference in height that was formed by the wiring 5 [FIG. 2, (c)].Thereafter, by means of the polishing apparatus, this oxide film 7 wasso polished as to provide a smooth surface, using the polishing slurryprepared in the above step (1). Thus, a semiconductor substrate member 9having an interlayer insulating film 8 having a smooth surface wasobtained.

Finally, this substrate member 9 was washed with water by means of abrush washing assembly manufacture by Dainippon Screen Mfg. Co., Ltd. toremove abrasive grains remaining thereon, and thereafter the surface ofthe oxide film 7 was observed with an optical microscope and a scanningelectron microscope. As the result, neither scratch nor abrasive grainburied in the oxide film 7 was seen, and it was confirmable that theoxide film 7 was provided with a good smoothness when any polishingslurries of Examples 1 to 12 were used.

Percentage of rejects of semiconductor substrate members obtained in therespective Examples was smaller by 5% than a case in which substratemembers were polished using a conventional polishing slurry (silicaparticles of a primary particle diameter of 30 nm and a secondaryparticle diameter of 150 nm were used as abrasive grains, which weredispersed in an ammonia solution with a pH adjusted to 11) Thus, it hasbecome apparent that the polishing slurries of the above Examples enablemanufacture of semiconductor products in a high quality and at a highyield.

While we have shown and described several embodiments in accordance withour invention, it should be understood that disclosed embodiments aresusceptible of changes and modifications without departing from thescope of the invention. Therefore, we do not intend to be bound by thedetails shown and described herein but intend to cover all such changesand modifications fall within the ambit of the appended claims.

What is claimed is:
 1. A method for polishing a surface of asemiconductor substrate member, comprising: polishing said surface usinga polishing slurry comprising a dispersion medium and abrasive grainsdispersed in the dispersion medium, said abrasive grains consisting of acrystal material precipitated in said dispersion medium and having asolubility in the dispersion medium, at 25° C., of at least 0.001 g/100g.
 2. The method according to claim 1, wherein said abrasive grainscontain at least one selected from the group consisting of Ag compounds,Al compounds, As compounds, Ba compounds, Be compounds, Br compounds, Cacompounds, Cd compounds, Ce compounds, Co compounds, Cr compounds, Cscompounds, Cu compounds, Fe compounds, Ge compounds, B compounds, Clcompounds, P compounds, Hg compounds, In compounds, K compounds, Licompounds, Mg compounds, Mn compounds, Mo compounds, NH₄ compounds, Nacompounds, Nd compounds, Ni compounds, Pb compounds, Pr compounds, Ptcompounds, Rb compounds, Sb compounds, Se compounds, Sm compounds, Srcompounds, Th compounds, Tl compounds, U compounds, Y compounds, Ybcompounds, Zn compounds and I₂.
 3. The method according to claim 1,wherein said abrasive grains are comprised of organic material having amelting point of at least 30° C., wherein said organic material containsat least one selected from the group consisting of organic acids,organic acid esters, organic acid salts, ammonium oxalate, alcoholcompounds, ether compounds, phenolic compounds and nitrogen-containingcompounds.
 4. The method according to claim 1, wherein said dispersionmedium is: (1) an acidic solution containing at least one acid selectedfrom the group consisting of hydrofluoric acid, hydrochloric acid,sulfuric acid, nitric acid, acetic acid and organic acids other thanacetic acid; (2) an alkaline solution containing at least one baseselected from the group consisting of ammonium hydroxide, potassiumhydroxide, sodium hydroxide and amines; (3) a solution containing a saltof the above acid with the above base; (4) water; or (5) an organicsolvent.
 5. The method for polishing a surface of a semiconductorsubstrate member, comprising: polishing said surface using a polishingslurry that comprises a dispersion medium and abrasive grains dispersedin the dispersion medium, wherein the abrasive grains are a crystalprecipitated in said dispersion medium wherein said abrasive grains maybe dissolved in part in the dispersion medium, so as to vary thequantity of dispersion of the abrasive grains dispersed in the polishingslurry in the form of a solid.
 6. The method for polishing a surface ofa semiconductor substrate member, comprising: polishing said surfaceusing a polishing slurry that comprises a dispersion medium and abrasivegrains dispersed in the dispersion medium, wherein the abrasive grainsare a crystal precipitated in said dispersion medium and wherein thesolubility of the abrasive grains in the dispersion medium is varied bychanging the temperature of the polishing slurry, so as to vary thequantity of dispersion of the abrasive grains dispersed in the polishingslurry in the form of a solid.
 7. The method of claim 1 wherein thepolishing slurry is a saturated solution of compounds of said abrasivegrains in said dispersion medium.
 8. The method of claim 5 wherein thepolishing slurry is a saturated solution of compounds of said abrasivegrains in said dispersion medium.
 9. The method of claim 6 wherein thepolishing slurry is a saturated solution of compounds of said abrasivegrains in said dispersion medium.
 10. The process of claim 1 wherein thepolishing slurry does not contain a substance having a solubility in thedispersion medium at 25° C. of 0.001 g/100 g or lower.
 11. The processof claim 1 wherein the abrasive grains are made of a material selectedfrom the group consisting of NH₄Cl, NH₄ClO₄, NH₄HCO₃, Ce₂(SO₄)₃, CuCl₂,CuSO₄, adipic acid, citric acid monohydrate, succinic acid, ammoniumoxalate, sucrose, and malonic acid.